THIS IS A BUTTERFLY! (Scanning Electron Microscope) - Part 2 - Smarter Every Day 105

[music] Hey, it's me Destin. Welcome back to Smarter Every Day. I am crossing the street in Atlanta, Georgia. You can see the dome in the background, and I'm at Georgia State University, and I've got a box of butterfly wings. I'm trying to unravel a mystery that I uncovered in the rainforest. We discovered that when we dropped a butterfly and he started to fly off, pixie dust would fly off his wings. At least that's what I call it. Check it out. [music]

So to figure out what this is, we came to the Petit Science Center here at Georgia State University. We're going to the biological imaging center. Dr. Simmons? Nice to meet you. - Good to meet you. - I brought you some butterflies. - Oh cool. (Destin) Ooh, so this is where you work, huh? - This is where I live. - Let's do it. - Come on in. - So if you watched the last episode, you're aware that these little dust particles are actually scales coming off the butterfly's wings. What we don't know, however, is how those scales are attached to the wing in the first place. Dr. Simmons happens to be an expert microscopist, and he's agreed to give us a little lesson in scanning electron microscopes.

So Dr. Simmons just drew all this, and I'm gonna try to summarize it. You tell me if I get this wrong, OK? - OK. - OK, so we have tungsten up here. We start a flow of electrons here, and as it comes out, we go through what you're calling electromagnetic lenses? - Yes. - OK, and so we vary the beam and then we start to scan that beam across whatever it is, in this case, a butterfly wing. - Butterfly wing. - Depending on where we are in the scan, we measure how many secondary electrons we get off the sample using our electron multiplier? - It's sort of an electron detector. - And then we run that through some filters, and we're able to get a grey scale image. Is that basically it? - That's basically it. - We are now experts on scanning electron microscopes. Would you say that? - Oh yeah. - [laughs] Alright, time for science. Goggle up. Probably the coolest goggles I've ever been given, not gonna lie.

OK, here's the question. We have three different types of butterfly wings here. We have a sunset moth, which technically isn't a butterfly. We have a morpho butterfly wing, and then we have a cithaerius. What we're gonna do is Dr. Simmons is gonna use the scanning electron microscope to show us the difference in the wings. Now, what I think is interesting about the cithaerius is that it goes from a scaled wing to a transparent wing. - The unfortunate thing here is that this is destructive testing. - It is what it is, man. We gotta do it. [music]

(Destin) On the scanning electron microscope, we're gonna be bombarding it with electrons, and you're gonna have this huge charge difference. But the problem is butterfly wings are insulators, am I saying this right, Dr. Simmons? - You got it. - Alright. So we have to discharge that voltage, or I guess it's just potential. We have to discharge that back to ground, and the way we do that is we have gold all over the butterfly wing, so that it has a path to ground. Can you give me a countdown to science? - OK. 3.. 2.. 1.. I'm gonna hit start. - Cool. So that's a gold cloud? - These are golden and palladium atoms flying around in an ionized argon atmosphere. -Looks a little different. - Looks a little different. That's got a fairly heavy coat on it. - So that's gold. - 60% gold, 40% palladium. (Destin) Alright, here we go. It's taken Dr. Simmons years of experience in biology, physics, and optics to create.. this.

[music] Check it out. You can see that these two butterfly scales right next to each other have different textures. The little holes in the one on the right are less than a micron across. Now, I've heard that butterfly wings are colored by holes in them, so you'd think that the one on the right is colored, right? Well, I did a little cross check and I figured out that the ones with the open lattice structure are actually black. Because SEM uses electrons instead of light, it can't provide color, so it's common for scientists to create false color images to help people understand what they're looking at. Check it out again, this time with false color.

OK, let's look at the morpho. You can see that the tops of the wings are blue, but the bottom has some kind of brownish-tan color. If we scan it, we can see that these tan scales have small holes in them, but the blue scales have some kind of ridge in them. Now, if we measure the width of these ridges, it turns out that it's at the exact same wavelength as yellow light. White light minus yellow light is equal to blue light, so somehow these ridges are removing the yellow light and making the wing look blue. If we were to take this scale and cut it right here and go look along those ridges, kind of like we're looking through a canyon, you would see a baffled nanostructure that's amazing.

As white light comes in, this nanostructure is the perfect size to interact with the wavelength of visible light and strip out the yellow. That leaves blue left, and that's where the morpho gets its color. On this goliath birdwing butterfly, those baffled nanostructures strip out the red and the blue, which leaves you with green. After thinking about this, I realized that if I were to somehow fill up these baffles so that they couldn't interact with the light, I should be able to see the pigment of the wing as it really is instead of this pseudocolor. So here we go. When I coat the wings with isopropanol, you can see that the wing loses its irradiance because these nanostructures fill up. But as soon as it evaporates off, these brilliant colors return.

So there you have it. Butterflies use nanotechnology to lie about their color. But we still haven't answered our question. How are these scales attached to the wing? Like this. It's almost as if someone deliberately planted trees in a nice evenly spaced row. I think it's beautiful. Through normal wear and tear, even aerodynamic drag along the wings, these scales are somehow plucked out of these roots, leaving these hollow stumps. So every time you rub a butterfly wing, that's what you're doing. You remember that cithaerius I was talking about, right? It's got scales on one side, and it gradually fades to a transparent wing.

So I took some photos under my microscope to figure out exactly what colors we should use for the false color, and I discovered that not only are there scales, but there appears to be some type of hairs. When I took this to Dr. Simmons, I learned two things. Number one, I know the color of the scales are pink because I took a picture of it, but they have those hole structures like we saw earlier. That's weird. So it looks like there's actually pigment involved. And number two, the hairs are not hairs. I mean, look at this thing. That is crazy. What is going on and why? I mean, there's a nanostructure, but it doesn't appear to be an optically driven phenomenon because this is on a transparent part of the wing. Why would the butterfly need this?

I mean, the information required to build something like this, and the energy that goes into something like this is incredible. So why does he need it? For just a second, let's all agree on this. Something as simple as a butterfly contains complicated mysteries that you and I will never understand. And that.. that's beautiful. Wow. That's awesome.

So thank you very much for your time. A video like this is very hard to put together, and often it requires a lot of people, like Dr. Simmons, for example, genius. There is also Larom, who colorized all the SEM images, which are on the Facebook page if you'd like to download them yourself. Also, Henry from Minute Physics. He took the time to make that zoom animation for me. I couldn't have done that myself, that was great. Gordon wrote the music, just a lot of people. But probably most importantly is audible.com, because they provide money for me to do things like drive to Atlanta, so they are sponsoring Smarter Every Day.

So if you would consider helping audible.com like Smarter Every Day by downloading a free audiobook, go to audible.com/smarter. Check out all their titles, there's like 100,000 of them. I was looking at one right now, The Shark's Paintbrush: Biomimicry and how nature is inspiring innovation. There's some biomimicry stuff here I'm gonna talk about in the next episode that I think you'll like, but anyway more importantly go check out audible.com/smarter, consider downloading a book, that helps Smarter Every Day out. You're smart people, you know what's going on here.

Anyway, I'm Destin, you're getting Smarter Every Day. Thanks for your time. Have a good one. (Destin) Did she not just say she wanted to be on the video? - You want to get the maximum likes, you need to put me on your video. - Really? You have no idea. There's nothing on this little caterpillar that looks even remotely like a butterfly scale, but somehow he gels inside of his cocoon and his pupa, and he creates nanostructures. Oh, he's moving. So here he is... Oop! [laugh]

(Destin) What are you drawing down there? - The butterfly's scales. - Where are the scales at? - On the wing. - How do you know that? - Because you're making a video. - [laughs] (Destin) Right now? - Yes. [laughs] Alright, so obviously I get maximum likes now because "Princess" is in the video, right? - Byeee! - Byee! [Captions by Andrew Jackson] captionsbyandrew.wordpress.com Captioning in different languages welcome. Please contact Destin if you can help.